One-Step Hydrogenation−Esterification of Aldehyde and Acid to Ester over Bifunctional Pt Catalysts: A Model Reaction as Novel Route for Catalytic Upgrading of Fast Pyrolysis Bio-Oil

The bio-oil from fast pyrolysis of biomass cannot be used effectively as engine fuel because of its high corrosiveness and instability mainly due to substantial amounts of organic acids and reactive aldehydes. In this paper a treatment of acids and aldehydes in the bio-oil was focused on. A novel upgrading method named one-step hydrogenation−esterification (OHE) was established to convert acids and aldehydes to stable and combustible components. Acetaldehyde (butyl aldehyde) and acetic acid were chosen as model compounds for the OHE reaction over platinum catalysts that acidic supports such as HZSM-5 or amorphous aluminum silicate were adopted. The catalysts were bifunctional, which means they have properties of hydrogenation and esterification. Experiments showed this, and it was a feasible route to convert these main unstable components of bio-oil to esters through this simple and effective OHE reaction. The catalysts with high surface area, large pore size distribution, small metal particles,and strong acid sites may be beneficial for the OHE reaction.